SPECIES INFORMATION SHEET Somateria mollissima English name: Scientific name: Common eider Somateria mollissima Taxonomical group: Species authority: Class: Aves Linnaeus, 1758 Order: Anseriformes Family: Anatidae Subspecies,Variations,Synonyms: Generation length: 7 years Somateria mollissima mollissima Past and current threats (Habitats Directive Future threats (Habitats Directive article 17 article 17 codes): codes): Breeding: Epidemics/Diseases (K03.02, K03.03), Breeding: Epidemics/Diseases (K03.02, K03.03), Alien species (I01), Climate change (M01, M02), Alien species (I01), Climate change (M01, M02), Competition and predation (K03.04, I02) Competition and predation (K03.04, I02) Wintering: Bycatch (F03.02.05), Oil spills Wintering: Bycatch (F03.02.05), Oil spills (H03.01), (H03.01), Hunting (F03.01), Extra-regional Hunting (F03.01), Extra-regional threats (food threats (food shortage in North Sea, XO), Human shortage in North Sea, XO), Human disturbance disturbance (G01.01), Mining and quarrying (G01.01), Mining and quarrying (C01.01), (C01.01), Construction (C03.03, D03.03), Water Construction (C03.03, D03.03), Water traffic traffic (D03.02) (D03.02) IUCN Criteria breeding: HELCOM Red List VU A2abe Category breeding: Vulnerable IUCN Criteria wintering: HELCOM Red List EN A2b Category wintering: Endangered Global / European IUCN Red List Category EU Birds Directive: LC / LC Annex II B (DK, EE, FR, IE, FI, SE ), Annex III B Protection and Red List status in HELCOM countries: Hunting not allowed in all EU Member States (Annex II B). Denmark: LC (on the 1997 Danish Amber List as a species of national responsibility outside the breeding season), Estonia: NT, Finland: NT, Germany:“particularly protected” under Federal Species Protection Decree (Bundesartenschutzverordnung)/*(Not threatened), Latvia: –, Lithuania: –, Poland: –, Russia: –, Sweden: NT (breeding) Range description and general trends The common eider (Somateria mollissima) breeds in coastal areas of north-west and northern Europe. The population has increased almost throughout the 20th century until the 1990s. Simultaneously, the species has also extended its breeding range southwards along the European Atlantic coast. However, since the mid-1990s a considerable decline of the breeding population has been observed in the northern Baltic (Finland, Sweden, Estonia). Common eiders are partially migratory and dispersive and winter mainly in marine or brackish areas. Successful adaptation to arctic conditions enables wintering displacement mostly within the breeding range. In Central Europe, common eiders overwinter in their breeding areas or show various migration patterns, depending on the area of origin (BWPi 2004, Mendel et al. 2008). The main wintering areas are in the Baltic Sea, along the west coast of Norway and in the Wadden Sea. The Baltic/Wadden Sea flyway population that mainly breeds in Finland, Sweden, Denmark and Estonia winters in the Inner Danish waters, the German Baltic Sea areas and in the Wadden Sea. The winter population has undergone a considerable decline of 36% from c. 1.2 million birds in 1990 to c. 760 000 birds in 2000, but was currently estimated at c. 976 000 individuals (Ekroos et al. 2012, Wetlands International 2012). © HELCOM Red List Bird Expert Group 2013 www.helcom.fi > Baltic Sea trends > Biodiversity > Red List of species SPECIES INFORMATION SHEET Somateria mollissima Somateria molissima. Photos by Ritzel Lutz (left) and Nicole Sonntag (right). Distribution and status in the Baltic Sea region Breeding The Swedish breeding population was estimated at 170 000 breeding females in 1973 and increased to 270 000 in 1983–1984 (Desholm et al. 2002). Since the end of the 1990s, the population has been declining. Currently, it is estimated at 120 000–200 000 breeding females (bf). Within the last 20 years the decline has been estimated to 25%. In Finland, the common eider was few in numbers in the 1910s and 1920s, but in the late 1930s the population was already estimated at 12 000 pairs. During World War II the population collapsed due to intensified hunting, egg collection, oil disasters as well as severe winters. After the war the population started to grow again with high growth rates. The increase was most rapid during the 1970s and 1980s, averaging 7–10% per year. In 2001, the total Finnish population was estimated at 150 000–180 000 breeding females, of which about 150 000 bred in the south-western archipelago, 10 000–20 000 in the Gulf of Finland, and less than 10 000 in the Bay of Bothnia. During the late 1980s and 1990s, no further increase occurred in the Gulf of Finland, and since the mid- 1990s the entire Finnish population is estimated to decline. For 2010, the population number was estimated at 103 000 breeding females, and the recent decline (2000–2010) to 2.3% p.a. In the St Petersburg region of Russia the species recovered during the 1970–90s. However, the population is still small and is estimated at 200 breeding females on the islands of the eastern part of the Gulf of Finland (A. Kondratyev, in litt.). At Lake Ladoga, the eider breeds in the Valaam archipelago and on small islands in the northern part of the lake. However, these areas belong to Karelia, not to St Petersburg region. In Estonia, the common eider is the second numerous duck species, breeding all over the archipelago. The population increased from the beginning of the century until 1940. During World War II and the post-war period the population decreased, but began to recover and expand its range in the mid-1950s. In the mid-1960s, the population was estimated at 3 000–3 500 breeding females, until the beginning of the 1980s it had increased to about 8 000, and c. 15 000 in 1995. However, after this peak it decreased to 12 000 in 2001 (Desholm et al. 2002, Elts et al. 2003; Fig. 5), and 3 000–7 000 breeding females in 2003–2008 (Elts et al. 2009). In the Kaliningrad region of Russia, Lithuania and Latvia the eider has not yet been recorded as a breeding bird. In Poland, the breeding of eiders is exceptional, there has been only one breeding record near Gdańsk in 1997 (Tomiałojć & Stawarczyk 2003). In Germany, the eider mainly breeds at the North Sea (1 100–1 300 bf in 2005, Südbeck et al. 2009). The © HELCOM Red List Bird Expert Group 2013 www.helcom.fi > Baltic Sea trends > Biodiversity > Red List of species SPECIES INFORMATION SHEET Somateria mollissima German Baltic Sea coast was not colonized before 1985. Since then, the eider breeds regularly there with increasing numbers in both Baltic coastal federal states, Mecklenburg-Western Pomerania and Schleswig-Holstein. In 2011, the population in Mecklenburg-Western Pomerania was 85–100 bf. In Denmark, the eider has shown a long-term increase during the 20th century. The breeding population was about 1 200–1 500 nesting females around 1935, 3 000–3 500 around 1960, 19 000–20 000 around 1980, and 23 000–25 000 around 1990. The annual growth rate was as high as 8–10% during the period 1960–1980, but slowed down to 2–3% in 1980–1990 (Lyngs 2000). During the 1990s until 2010, the population was about stagnant, giving an estimate of 24 000–25 000 breeding females in 2010 (Christensen & Bregnballe 2011; Fig. 5). However, the stability of total numbers does not reflect a stable situation, since some old, large colonies decreased considerably, whereas increases occurred on a number of small and newly established breeding sites. On Ertholmene (Bornholm), for instance, one of the largest and oldest eider colonies in Denmark, the number of nesting females dropped down from 3 000 in 1992 to 1 650 in 2007 (http://www.chnf.dk/lister/yffugle_chroe.html). 25000 Denmark 20000 Estonia 15000 10000 5000 breeding breeding females 0 1930 1940 1950 1960 1970 1980 1990 2000 2010 year Fig. 5. The development of the eider population in Denmark and Estonia during the 20th century. Data from Desholm et al. (2002) and Christensen & Bregnballe (2011). Between 1990 and 2000, the Baltic/Wadden Sea flyway population has undergone a considerable decline. In the Danish waters, the second most important wintering area of the flyway population, the number of wintering birds has declined from c. 800 000 to 370 000 during this time. Mid-winter counts suggest that the total population could have fallen from c. 1.2 million birds in 1991 to c. 760 000 in 2000, which means a reduction of 36% (Desholm et al. 2002) However, although reductions in breeding numbers are evident for some sites, the decline of the breeding population along the flyway seems to be less pronounced compared to the winter population. Shortcomings of the monitoring of breeding and wintering numbers, as well as an unknown buffering effect of non-breeders (i.e. earlier debut breeding attempt of subadults) are probably the reasons for the difference (Desholm et al. 2002). However, Finnish ringing data indicate no age-related buffering effect, whereas there was a true shortcoming of subadults in the south due to exceedingly small cohorts on the northern breeding grounds preceding the low winter counts in Denmark (Hario & Rintala 2009). Table 1: Population numbers of the common eider in the Baltic Sea area (numbers refer to breeding © HELCOM Red List Bird Expert Group 2013 www.helcom.fi > Baltic Sea trends > Biodiversity > Red List of species SPECIES INFORMATION SHEET Somateria mollissima females). For population trends 0=stable, -=decreasing, +=increasing, ?=unknown. Population size Short-term Long-term Country population trend population trend Breeding females Year (10 years) (50 years) Sweden 120 000–200 0001 2010 - + Finland 103 000 2010 - + Russia, PET 200 2010 ? + Estonia 3 000–7 000 2003–2008 - + Poland One breeding record 1997 Germany, SH 70 2005–2009 + + Germany, MV 85–100 2011 + + Denmark 24 000–25 000 2010 0 + Baltic Sea 250 000–335 000 Wintering Birds breeding in the Baltic region winter mostly in the western parts of the Baltic Sea.